What do you call the word at end of a prepositional phrase?

The word at the end of a prepositional phrase is called the object of the preposition.

Here's why:

* Prepositional phrases start with a preposition (like "on", "in", "at", "to", "from", etc.) and end with a noun or pronoun.

* The noun or pronoun acts as the object of the preposition, because it receives the action of the preposition.

Example:

* "The cat sat on the mat."

* "on the mat" is the prepositional phrase.

* "mat" is the object of the preposition "on".